From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org
Cc: mikey@neuling.org
Subject: [PATCH] powerpc, perf: Clear out branch entries to avoid any previous stale values
Date: Mon, 6 May 2013 13:34:40 +0530 [thread overview]
Message-ID: <1367827480-5375-1-git-send-email-khandual@linux.vnet.ibm.com> (raw)
The 'to' field inside branch entries might contain stale values from previous
PMU interrupt instances which had indirect branches. So clear all the values
before reading a fresh set of BHRB entries after a PMU interrupt.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
---
arch/powerpc/perf/core-book3s.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index c627843..09db68d 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1590,6 +1590,8 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
if (event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK) {
struct cpu_hw_events *cpuhw;
cpuhw = &__get_cpu_var(cpu_hw_events);
+ memset(cpuhw->bhrb_entries, 0,
+ sizeof(struct perf_branch_entry) * BHRB_MAX_ENTRIES);
power_pmu_bhrb_read(cpuhw);
data.br_stack = &cpuhw->bhrb_stack;
}
--
1.7.11.7
next reply other threads:[~2013-05-06 9:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-06 8:04 Anshuman Khandual [this message]
2013-05-06 12:53 ` [PATCH] powerpc, perf: Clear out branch entries to avoid any previous stale values Michael Ellerman
-- strict thread matches above, loose matches on Subject: below --
2013-05-06 6:59 Anshuman Khandual
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